The, optionally automatic, stacking of a base or carrier, in particular a pallet or a trolley, with packed items to form a stack for subsequent dispatch, i.e., “palletizing” is known per se. However, in this case, packed items having a uniform size or dimension are placed manually or by robots, grabs, etc., in locations determined by computer.
In contrast, the process of loading a load carrier with packed items with different characteristics to form a stack is the so-called “mixed-case” palletizing.
Current distribution logistics place ever increasing demands upon the picking process. Therefore, it is necessary to develop picking systems which process orders automatically without manual intervention.
To this end, automatic systems are being used ever more frequently for palletizing purposes. Such systems are known, e.g., from EP 1 462 394 B1, WO 2010/059923 A1 and WO 2008/068264 A1 or even WO 2014/005895 A1.
Thousands of different products (or packed items) with the most varied characteristics (size, shape, weight, dimensions, surfaces, solidity, etc.,) must be picked automatically with such systems.
Automated warehouses or goods distribution centers hold available a multiplicity of the most varied goods which, after an order has been placed, are compiled, i.e., picked, to produce a customised client delivery according to requirements.
In the goods distribution center, pallets holding one type of goods are generally delivered and temporarily stored. The pallets holding one type of goods generally comprise a plurality of packages which are palletized, e.g., in layers. For the purpose of temporary storage, so-called high-rack storage areas are often used which are designed as multi-level structures. The high-rack storage areas often use racking serving apparatuses in order in each case to remove a complete pallet from the high-rack storage area and to supply it to a singulating station. Other corresponding options for pallet storage are likewise feasible.
In this case, it is necessary to take account of different aspects which enormously increase the complexity compared with the “simple” manual stacking of simple regular geometries. For instance, a subsequent packed item can be stacked or placed effectively onto preceding packed item only if the latter has a flat or planar surface which should also be oriented approximately horizontally, and if the packed item can support the weight of the further packed items placed on it without incurring damage.
Furthermore, the formed stack should have a certain stability, inter alia to ensure that it does not fall over when being transported. Film-wrapping does help but on its own cannot stabilise an incorrectly formed stack.
Moreover, customers are ever more frequently requiring stacks to be optimized by reason of a desired unloading sequence. To this end, it has been found that a so-called shop-layout of the warehouse is advantageous. Particularly, in the food sector, warehouses are organized in this manner because the product range therein is extremely high and the unloading sequence in the supermarket is specified. In the case of a shop-layout, the different products are arranged as in the shop, i.e., grouped according to product families and arranged in specific aisles corresponding to the sequence on the shop floor. In other words, the different goods are thus arranged in the warehouse grouped in the aisles in the same sequence as in the supermarket aisles. In the warehouse, different goods are arranged or stored or organized into common groups of goods in spatial proximity, typically in the same or adjoining aisles.
In addition, the problem in the case of a shop layout of the warehouse in the distribution center is the change of flow and the distribution of the goods associated therewith. The goods are no longer distributed homogeneously across the warehouse or randomly but rather are organized in specific item groups in aisles, wherein the arrangement in the aisles is itself random.
The palletizing algorithms and machines used for forming stacks permit already relatively stable stacks having a specified order to be formed and have very high outputs or throughputs.
However, they may require a continuous flow of products from the corresponding aisles, for which reason they need replenishment or have to be filled.
It is also necessary to take into account a distribution of an order onto a plurality of pallets, as is generally the case when supplying goods to supermarkets.
Typically, the palletizing devices comprising goods are supplied to a warehouse as follows:
Initially, pallets holding one type of goods are delivered to the incoming goods area and temporarily stored. The pallets holding one type of goods generally comprise a plurality of packages which are palletized, e.g., in layers. For the purpose of temporary storage, the pallets are transported to high-rack storage areas where racking serving apparatuses are used for placing the pallets into storage or removing them from storage.
If goods are required from the corresponding pallet, the pallet is removed from storage and is depalletized mostly layer-by-layer in a depalletizer and subsequently the goods are singulated.
Then, the goods are temporarily stored in a buffer storage area until a corresponding order is actually waiting to be processed or all of the goods are in stock. The buffer storage areas are typically automatic small parts warehouses or shuttle warehouses in which the goods can be removed from storage individually and in a controlled manner according to a specified sequence (influenced, e.g., by the loading sequence on the pallet).
If an order has been placed, a stacking arrangement of the pallet or of the trolley is calculated on the basis of the ordered goods and the desired sequence of unloading, for which reason a palletizing algorithm of the warehouse management system establishes in advance a sequence and arrangement of the individual goods in the stack.
Subsequently, the different articles/goods are retrieved from the buffer storage area and are supplied in the calculated sequence to a palletizing machine or a manual palletizing device.
The goods which are now no longer present in the buffer storage area are then replenished from the pallet warehouse.
To this end, the goods are classified according to turnover rate and optionally further criteria (e.g., volume) and the number of parts to be depalletized (whole pallet, half a pallet, one layer, etc.,) is determined. This method together with the other warehouse strategies (cf. above), in particular the shop layout, ensures that the goods structure fluctuates from aisle to aisle in the buffer storage area (many slow-rotating items vs. few fast-rotating items or small goods vs. large goods). Therefore, capacity is lost in the storage aisles of the buffer storage area and goods which are required cannot be accommodated.
The turnover rate (fast-moving items vs. slow-moving items) of the goods can be established, e.g., by means of ABC analysis.
To date, replenishment has been performed merely statistically based on history; it is thus imprecise and possibly incorrect. Anticipatory forecasting to enable the supply of sufficient quantities is possible, e.g., only for about 3 to 4 hours. Therefore, bottlenecks can occur and so the palletizing machines are not able to call on their full capacity. To date, this supply aspect has not been addressed satisfactorily.
Therefore, one object of the present disclosure is to provide a supply method for palletizing machines in distribution centers, by means of which the supply to palletizing machines can be improved, even if the distribution center utilizes a shop layout.